Tapping machine



P 11, 1951 E. B. ELDER 2,567,511

TAPPING MACHINE Filed April 16. 1945 8 Sheets-Sheet l IN VEN TOR.

Sept. 11, 1951 E. B. ELDER 2,567,511

TAPPING MACHINE Filed April 16, 1945 a Sheets-Sheet 2 109 125 5' 38 C 1a as, $9 59 14 uwuvron.

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Septlflll, 19 51 5. B. ELDER 2,567,511

TAPPING MACHINE Filed April 16. 1945 8 Sheets-Sheet 5 Fig- , INVENTOR. 105 5:431. .fifiZDEQ,

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P 19,51 E. B. ELDER 2,567,511

TAPPING MACHINE Filed April 16. 1945. 8 Sheets-Sheet 4 I INVENTOR. 52191. 5 2,052,

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p 11, 1951 I E. B. ELDER 2,567,511

TAPPING MACHINE Filed April 16, 1945 8 Sheets-Sheet 5 IN VEN TOR.

' ATTOQNEY.

Sept. 11, 1951 E. B. ELDEI 2,567,511

TAPPING MACHINE Filed April 16, 1945 a Sheets-Sheet 6 INVENTOR. 5 5221. .5? 52052,

E. B. ELDER TAPPING MACHINE Sept. 11, 1951 Filed April 16, 1945 8 Sheets-Sheet '7 \lllllfilllllllll...

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Sept. 11,- 1951 E. B. ELDER 7 2,567,511

TAPPING MACHINE Filed April 16,1945 I 8 Sheets-Sheet 8 E I z 15 1a J55 g CJ NVENTOR. 224 3 Lose,

ATTOQNEX Patented Sept. 11, 1951 UNITED STATES PATENT OFFICE TAPPING MACHINE I am is. Elder, Arcadia, cam. Application April 16, 1945, Serial No. 588,488

7 Claims. 1

My invention relates to tapping machines, and relates inparticular to a tapping machine unit or head which may be supported on the pedestal of many standard drill presses.

It is an object of the invention to provide a tapping machine by which a large number of different standard threads may be cut without the necessity of replacing any operative part of the device-other than the replacement of the tap itself--when the operation of a tap of different size is required. The invention has as an important advantage in enabling the operation of many different sizes of taps without the necessity of changing lead screws and half nuts. The operator merely places the desired tap in thetappingdevice and adjusts cooperating parts of the device in accordance with the pitch or lead of the tap which is being used.

An object of the invention is to provide a tapping machine having a spindle for holding and rotating the tap, a single lead screw for producing axial movement of the spindle, and a speed change mechanism through which the lead screw is driven, this speed change mechanism rotating the screw at such different speeds that a large variety of speeds for a' corresponding variety of tap thread sizes may be attained. For example, in the applicants device it is possible by the use of a single leadscrew to' cut nineteen diiierent standard threads, embracing all or the standard thread pitches from eight to fifty-six inclusive.

An object of the invention is to provide atap ping machine having a spindle which is moved axially by a lead screw driven through a speed change mechanism, this tapping machinehaving means for compensating for the lost motion or play which must necessarily occur in the gear train of the speed change mechanism.

It is an object of the invention to provide a tapping machine having a drive connection for a tap, whereby the tap is connected to the rotating spindle, this drive connection having a limited rotary free play, so that relative rotary movement of the spindle and tap are provided to compensate for the lost motion in the speed change mechanism. In the present invention, using a single lead screw so that the necessity for changing the lead screw each time the tap size is changed becomes unnecessary, the compensatory action permits the backing out of the tap from the tap hole without cutting or mutilating the threads during the reverse motion of the tap. It is possible, therefore, consistently and continuously to tap holes within close toler- 83-1685.

An object of the invention is to provide a tapping machine having the ability to pick up the thread in a previously tapped hole without damaging the thread and maintaining the desired class of fit, and without regard to the orientation of the parts in the jig, providing the part is held axially aligned with the spindle. For example, it is possible to first rough tap blind holes, clear out the chips, and then go back into the holes with a finishing tap, which finishing tap will pick up the roughed thread and produce a finishing cut on the thread, with a great uniformity as to depth, size, and finish of the threads.

It is an object of the invention to provide a tapping machine having a forward and reverse clutch, with automatic means for actuating the clutch, the clutch being of such sensitiveness and responsiveness to control that in the tapping of a thread to a prescribed depth, the spindle may be stopped within one quarter revolution of the predetermined stopping point.

An object of the invention is to provide a ta p' ping machine having automatic stops for controlling the rotation and axial movement of the spindle, which may be changed from automatic to manual operation, or from manual operation to automatic operation without changing the positions of the automatic stops. I

It is an object of the invention to provide a tapping machine having novel means for supporting and adjusting the partial nutswhich engage the lead screw, whereby a closerunning fit is maintained between the lead screw and the partial nuts and a lapping of the threads of the partial nuts in engagement with the lead screw is accomplished.

An object of the invention is to provide a tapping machine wherein the stopping and starting of the tapping operation is done without the necessity of disengaging'and engaging the part-ial nuts from the lead screw, this device having a multiple-disc clutch which runs in oil and which cooperates with the control elements of the tapping machine and starts and stops the tapping operation. A further object of 'the invention is to provide a tap holder for connecting the tap to the spindle, this tap holder being so constructed that the tap is supported with a three way float. That is to say, the tap has guided limited relative movement in three directions. There is relative movement of the tap and spindle in axial direction to permit small differences in axial movement of the tap and spindle when the tap is in engagement with the work. There is rotary relative play of the tap and spindle to 3 compensate for lost motion in the drive for the lead screw, and there is a slight lateral play of the tap to allow for small disalignment of the opening to be tapped and the spindle.

Further objects and advantages of the invention will be brought out in the following part of the specification.

Referring to the drawings which are for 11- lustrative purposes only,

Fig. l is a side elevation of a preferred embodiment of my invention mounted on a pedestal.

Fig. 2 is a front elevation of the tapping machine.

Fig. 3 is an enlarged plan view of the forward portion of the tapping machine.

Fig. 4 is a section taken as indicated by the line 44 of Fig. 3.

Fig. 5 is an enlarged sectional view of the clutch of the device.

Fig. 6 is an enlarged cross section taken as indicated by the line 66 of Fig. 5.

Fig. '7 is an enlarged cross section taken as indicated by the line 1-'! of Fig. 5.

Fig. 8 is an enlarged cross section taken as indicated by the line 8-8 of Fig. 5.

Fig. 9 is an enlarged cross section taken as indicated by the line ,95 of Fig. 5.

Fig. 10 is an enlarged cross section taken on the line l0-l ll indicated in Fig. 5.

Fig. 11 is an enlarged cross section taken as indicated by the line I I--l l of Fig. 5.

Fig. 12 is a perspective view showing the ad justable collar of the clutch mechanism.

Fig. 13 is an enlarged cross section taken as indicated by the line l3-l3 of Fig. 5.

Fig, 14 is a section taken as indicated by the line l4|4 of Fig. 13.

Fig. 15'is a fragmentary section taken as indicated by the line l5-l 5 of Fig. 5.

Fig. 16 is an enlarged fragmentary sectional view showing the spindle and lead screw in association with cooperating parts.

Fig. 17 is a sectional view taken as indicated by the line I1-I'l of Fig. 16.

Fig. 18 is a sectional view taken as indicated by the line l8-l8 of Fig. 4, showing a plan of the gear'train of the speed change mechanism.

Fig. 19 is a sectional development of the gear train and immediately associated parts taken as indicated by the line Ill-l9 of Fig. 18.

Fig. 20 is an enlarged elevational view of that portion of the tapping machine adjacent the lower end of the lead screw showing the control levers of the device, with the clutch lever positioned for downward movement of the spindle and tap.

Fig. 21 is a fragmentary view showing the clutch lever and the down trip lever at the end of the tapping operation.

Fig. 22 is a fragmentary elevational view showing another position of these levers.

Fig. 23 is a slightly enlarged section taken on the plane indicated by the line 23-23 of Fig. 16.

In Figs. 1 and 2 I show my tapping machine l0 supported on a pedestal ll on which a work supporting table I! is adjustable. The machine ID has a main body [3 in which a spindle I4 is vertically movable. On the .upper portion of the main body l3 there is aspeed change mechanism l5, and to the rear of the body l3 there is a reversible clutch [6 which is actuated by a motor 11. Figs. 4 and 16 show the interior of the body l3. It has a vertical bore H3 in which a cylindric spindle carriage I9 is slidable, thiscarriage I9 having bearings 20 at the ends thereof tosupport the spindle l4. In the rear face of the carriage IS a rack 2| is out which rack is engaged by a gear 22 adapted to be rotated by the hand wheel 23, shown in Fig. 2, when manual vertical operation of the spindle is desired.

A splined spindle extension I4 is fixed on the upper end of the spindle I4, and projects upwardly through a sleeve or spindle quill 24 which is supported by bearings 25 and 26, the spindle extension [4' having splined engagement with the quill 24. The quill 24 has a gear 21 on its upwardly extending portion, and theupper end 28 of the quill is supported or guided by a bearing 29 which is held in the lower end of a tube 30, the upper end of which is fixed in a bracket 3|, as shown in Fig. 4.

In the main body "there is a bore 32 in which a leadscrew 33 is rotatable and axially movable. The lower end 34 of the lead screw 33 extends into a body 35 and is rotatably connected to the body 35, by radial bearing means 36 and thrust bearing means 31, enabling rotation of the screw 33 relatively to the body 35 and transmitting the vertical movement of the screw 33 to the body. This body 35 has a forwardly projecting arm 33 which is clamped onto the lower end of the spindle carriage l9 so that the vertical movement of the screw 33 will be transmitted through the body 35 and the carriage IE! to the spindle I4. The body 35 has, as shown in Figs. 1, 2, 16, and 20, an arm 39 carrying an upwardly projecting screw 40 with adjusting nuts 4| thereon, and an arm 42 which carries an upwardly projecting screw 43 having adjusting nuts 44 threaded thereon, the purpose of which will be hereinafter explained. The screw 33 has an upwardly projecting splined stem 45 which slides within and is rotated by a sleeve 46, the lower end of which sleeve is rotatively supported by a bearing 41, shown in Fig. 16. As shown in Fig. 4, the upper portion of the sleeve 46 has thereon a gear cluster 48 forming a part of the speed change mechanism.

As shown in Figs. 16 and 1'7, the main body [3 has therein a transverse opening 49 of rectangular cross section, this opening 49 intersecting the lower end of the bore 32 so that the opposite end portions of the opening 43 may serve as guides for ,blocks or carriages 50 which are slidable in these guides toward and away from the screw 33. Each carriage 50 has an opening 51 in which a partial nut 52 is adjustable toward and away from the screw 33 so as to make proper working engagement with the screw 33, by means of an adjusting screw 53 which threads into the outer end of the carriage 50 and is rotatably held in a cap 54' secured in the outer end of the carriage 50. By rotation of the screws 53, the partial nuts 52 may be positioned so as to snugly engage the screw "33 when the blocks 50 are moved to their innermost positions. The carriages 50 are moved back and forth with relation to the screw 33 by crank means 54 which are duplicate in their characters but. are disposed at opposite hand. Each crank means 54 includes a cylindric body or disc 55 which is turnable in a cylindric open ing 56 in the side wall 51 adjacent the opening 49, each disc or body 55 having a peripheral channel 58 which is engaged by the inner end of a screw 53 to prevent the disc 55 from leaving the opening 56 in which it is turnable. Each crank member 54 includes a crank element 01' lever 60 which is secured to the associated disc an extension 62 which is bored to receive a pin 5 63, the inner end of which pin engages a vertical slot 64 in the adjacent carriage 59. In Fig. 16 and Fig. 17 the crank elements 54 are in perpendicular relation to the lead screw 33-that is to say,- they lie in a plane which is substantially perpendicular to the screw 33-and when in this position, the pins 63 thereof hold the carriages 59 in their closest relation to the screw 33, at which time the partial nuts 52 engage the threads of the screw 33. By rotation of the crank means 54, the pins 93 may be caused to move through arcs and to carry the members 59 outwardly from the locked positions in which they are shown with relation to the screw 33, thereby retracting the partial nuts 52 from the screw 33. For rotation of the crank means 54, links 65 are connected to the outer ends of the lever elements 69 of the crank means, these links 95 extending upwardly on opposite sides of the main body I3 and having their ends pivotally connected to the ends 66 of a bifurcated hand lever '61, the handle 68 of which is disposed at the front of the device, convenient for operation by the workman. The lever 61 swings on screws 69, and whenever desired, this lever 61 may be swung from the neutral position in which it is shown in Fig. 16, thereby transmitting motion through the links 65 to the crank means 54, so that the carriages 59 and the partial nuts 52, supported thereby, will be re-' tracted, and the lead screw 33 released so that it may have free vertical movement in the opening 32, as the spindle carriage I9 is moved vertically, as a result of rotation of the gear 22 in engagement with the rack 2 I. When it is desired to remove the carriages 59, for example, for the purpose of replacing the partial nuts 52, the pins 63 may be moved outward or removed from the levers 59 to disengage the slots 64 of the carriages 59.

As shown in Figs. 4, 1B, and 19, the speed itzharlige mechanism includes a second gear cluser 9 shifting gears H and 12 for transmitting rotation to the gear clusters 19 and 49 respectively. The shifting gear 1| is supported by means of a pin 13 on a lever 14 which swings around the axis of the gear 21, the shifting gear 1| being in continuous engagement with the gear 21. The lever 14 is mounted on the lower end of a tube 15 which is slidable and rotatable upon the tube 39 which supports the upper end 23 of the quill 24. On the upper end of the tube 15 there is a lever 16 which is manually swingable along a stepped plate 11. As shown in Fig. 3, the lever 16 is provided with a locking pin 18 movable into and out of engagement with the plate 11 by means of a small handle 99 pivoted on the outer portion of the lever 16. By means of the lever 16, the tube 15 may be rotated and shifted vertically, enabling movement of the gear 1| vertically with relation to the gear 21 and horizontally into engagement with any one of the separate gear elements of the cluster 19, thereby providing a speed change between the gear 21 and the shaft 19 on the lower end of which the gear cluster 19 is fixed.

The shaft 19 is supported in vertical position in addition to the gear cluster 48, and two 6 which is fixed on the lower end of the tube 83. The shifting gear 12 is in continuous meshed engagement with the gear 85, so that this gear 12 is caused to rotate whenever the shaft 19 rotates. The lever 89 may be rotated around the axis of the shaft 19, and may be moved vertically so that the gear 12 may be brought into engagement with any of the gear elements of the gear cluster 48, thereby providing a speed change between the shaft 19 and the shaft or sleeve member 46 which has splined engagement with the stem 45 of the lead screw 33.

The tube 83 has on its upper portion a lever 99 arranged to swing with relation to a stepped plate 9|. This lever 99, as shown in Fig. 3, has a locking pin 92 adapted to be moved into and out of engagement with the stepped plate 9| by a handle 93 which is pivoted on theouter portion of the lever 99. As the lever 99, by vertical and swinging movement, is adjusted along the stepped plate 9|, the tube 83 will be correspondingly moved so as to shift the gear vertically and also bring the shifting gear 12 into engagement with appropriate gear elements of the gear cluster 98.

As shown in Fig. 4, the motor I1, through adjustable belt and pulley means 94, drives the power input shaft of the clutch mechanism I6, and power from the clutch mechanism I6 is transmit-ted through the output sprocket 96 of the clutch mechanism I6 to a drive chain 91 which runs around a sprocket 98 which is fixed on the spindle quill 24. The power means of the tapping device accordingly drives the spindle and synchronously or simultaneously therewith drives the lead screw 33 through the gears of the speed change mechanism I 5, which receives power from the gear 21 which is formed on the quill 24 and is therefore rotated by the sprocket 99.

Referring now to Fig. 5, the clutch mechanism I6 has a shell 99 adapted to be filled with oil. In the upper part of the shell 99 there is a forward gear I99 and in the lower part of the shell 99 there is a smaller reverse gear I9I, both gears I99 and I9I being supported so as to rotate upon a vertical axis defined by a hollow shaft or tube I92. The power input shaft 95 of the clutch mechanism I6 is supported by a plurality of bearings I93, and in the upper part of the shell 99 the shaft 95 has a small pinion I94 in direct engagement with the forward gear I99, to drive the gear I99 at relatively slow speed. A pinion I95 fixed on the lower portion of the shaft 95'drives an idler I96 which is meshed with the reverse gear II, to drive the gear |9I at relatively high speed and in a direction reverse to the rotation of the gear I99. The gears I99 and I9I are fixed upon clutch shells I91 which are substantially identical and which extend toward a clutch body I98 which occupies a fixed position on the hollow shaft I92 substantially centrally between the gears I99 and NI. Upper and lower disc clutch assemblies I99 of identical form and construction are operative between the shells I91 and the clutch body I98, whereby the upper clutch shell I91 may be drivably connected to the body I99 to rotate the tubular shaft I92 in forward direction, or the lower clutch shell I91 may be drivably connected to the clutch body I98 to drive the tubular shaft I92 in reverse direction and at relatively higher speed. As shown in Fig. 13, the clutch body I99 has three channels II9 out thereacross in which blocks II I are fitted, these blocks being held in place by a ring II2, which extends around the body I99 and has set screws 3 to engage the blocks III. As shown in Fig. 5, each of the blocks III has sockets H4 in its opposite end to receive the rounded ends II5 of clutch actuating levers II6 which extend toward and into the ends of the shells I01.

Adjacent the upper and lower faces of the body I08 are annular inner disc supports II1 of the clutch assemblies I09, shown in section in Figs. 8 and 9. Adjacent the ends of the members II1 are collars I I8 lying within the enlarged portions of the shells I01, and supporting such portions for rotation on the axis of the tubular shaft I02. Each clutch assembly I09 includesa plurality of clutch plates or rings II9 having peripheral extensions I20 which extend into slots I2I in the shells I01 to prevent relative rotation of the plates H9 and the shells I01. The clutch assemblies I09 also include clutch rings or plates I22 having inwardly directed extensions or tongues I23 to engage slots I24 which are formed in the inner disc supports II1. I Between the assemblies of plates or discs H9 and I22 and in the upper and lower faces of the body I00 there are adjustable collars I25 adapted to be engaged by the short arms I26 of the levers II6 to apply pressure to the clutch disc assemblies when the levers I I6 are selectively rotated, for the purpose of selectively actuating the clutch means. Each of the adjustable collars I25 consists of a pair of rings I21 and I28 which fit together and which are so formed that relative rotation of these rings I21 and I28 will change the collar width, the purpose of changing the width of the collars I25 being to adjust the pressure exerted against the clutch disc assemblies when the associated levers II6 are swung inward to their maximum extent. Each ring I20 has several cam surfaces I29 formed thereon, such faces I29 being disposed helically. The rings I21 each have a number of projections I30 corresponding to the number of cam faces l29, to engage the faces I29 and slide thereon during adjustment of the collars. I

As shown in Figs. 13 and 14, the bodies I08 have longitudinal channels I3I, in which locking bars I32 are held in slidable relation by the ring I I2. Each of these locking bars I32 has an extension I33 for engaging a notch I34 in the periphery of a ring I21 and a reduced portion I35 for engagement with the toothed periphery segment I36 of the associated ring I28. Each locking bar I32 is held outward in the position in which it is shown in Fig. 14 by means of a spring I31, and

each locking bar I32 has a pin I36 projecting therefrom through a slot I38 in the ring M2 for manual engagement, whereby the locking bar I32 may be retracted a sufficient distance to disengage the end portion I35 thereof from the toothed segment I36 of the associated ring I20, to permit rotation of the ring I28 and thereby change the width of the adjustable collar I25. The rear ends of the springs I31 are restrained by filler pieces I38, as shown in Fig. 14.

Within each clutch shell I01 there is a slidable clutch actuator I39 having a lip I40 to engage the champfered ends of the long arms I4 I Each clutch actuator I39 is longitudinally slidable on the tubular shaft I02, and is provided with a key I42 which projects through a slot I43 in the tubular shaft I02 to engage a socket or recess I44 in a bar I45 which is axially slidable within the tubular shaft I02 and has its upper end I46 projecting from the upper end of the tubular shaft for engagement by a shifting means com-- prising a lever I41 which is swingable on a pin I48. When the shifting bar I45 is in the intermediate or neutral position in which it is shown in Fig. 5, the tubular shaft I02 and the parts sup ported directly thereon remain stationary, whereas the upper and lower clutch shells I01 are in continuous rotation so that the clutch rings or discs] I9 rotate with relation to the clutch rings or discs I22. When the bar I45 is moved downward a short distance from its position in Fig. 5, the upper clutch actuator I39 will engage the upper set of clutch actuating levers, to actuate the upper clutch assembly I09, whereupon the tubular shaft I02 willbe rotated in forward direction. An upward movement of the bar I45 from its neutral position will move the lower clutch actuator I39 upward to engage the lower set of clutch actuating levers II6 to actuate the lower clutch assembly I09, whereupon the tubular shaft I02 will be driven in reverse direction. It will be noted that the clutch actuating levers I I6 are not swung on pivot pins and accordingly have maximum strength at the point of joinder between the joint lever arms I26 and the long lever arms I4I thereof, where greater strain occurs. To accomplish this desired effect, the members II6 are articulated with relation to the clutch body I08 by the provision of the socket. I I4 to receive the extremities of the members I I6 and permit a limited rotation thereof without use of pivot pins.

The shaft I02 drives the sprocket 96 through a friction drive element I49, so that the torque applied to the tap which is being operated will be limited to the torque transmitting capacity of the friction drive-element I49. This friction drive element comprises a disc I50 which is keyed upon the upper portion of the tubular shaft I02,

a second disc I5I which is turnable on the tubular shaft I02 and is connected to the sprocket 96, a spring I52 and a nut I53 which isthreaded .upon the upper end of the tubular shaft I02 so as to be adjusted downwardly to compress the spring I52 to the desired extent. The lever I41 has upper and lower pairs of fingers I54 and I55 as shown in Figs. 5, l5, and 20. In the space between each upper finger I54 and lower finger I55 there is a slide block I56 which receives a trunnion I51 which projects from a body I58 in which the upper part of the bar I45 rotates. Above and below the body; I53 collars I59 are fixed on the bar I45 so that as movement of the lever I51 moves the body I58, vertically, such movement will be transmitted to. the bar I45 through the collars I59.

As best shown in Fig. 20, a clutch operating, handle I is provided, this handle I60 being located on the far side of the main body I3, and being fixed on the end of a transverse shaft IGI, which defines an axis on which the handle I60 may be swung between the three positions thereof shown in Fig. 20, wherein the handle I60 is shown in its down position, for operating the clutch so as to rotate the tap in forward direction and feed the tap downward. When the handle I60 is in this down position, the short lever I62 which is pinned on the shaft I6I rotates the lev r I41 in counterclockwise direction through a. pin interengagement I63, the bar I45 being accordingly moved downward so as to actuate the upper clutch assembly I09 shown in Fig. 5. A spring I64 urges the clutch operating handle I60 upward.

Upward movement of the clutch operating handle I6il'is prevented, as shown in Fig. 20, by a clutch latching mechanism which consists of a'finger I65, pinned on the near end of the shaft I6I and a latching lever I66 which is swingable 9 on ascrew Hi1 mounted in. the near face. or wall of. the. shell structure. of. the tanning machine. This. latching lever I68 has a shoulder I168 which engages the end of the finger I65 so as to. pre vent counterclockwise rotation of the. shaft III and keep the handle I 50 from swinging upward from the position in which it is shown in. full lines in. Fig. 20. The. rightward. exten ion I60 or the latching lever I68 carries a screw I10, which worksv in av slot I1I in the. upper end ot a link. I12 pivotally connected to. the. leftward end of a re.- leasing lever I13 which is hinged upon. a screw I14. The releasing lever L13. has. a. prominence I15 lying in the path of movement of the adiustlug nuts 44 of the screw 43.

As. the lead screw 33. travels. downward. in re.- sponse to. the forward actuation of the. device resulting from the movement of the handle I80 into its down position, the-nuts 44. move down.- ward toward the prominence I15, finally engaging the same as. shown Fig. 2.1,. and: swinging the releasing lever I13 in clockwise direction so as. to move the link I12 upward. The. upward movement of the link I12 is transmitted through the screw I10 to the latching lever I66, rotating the same in counterclockwise direction. so,- as to remove the shoulder I68 from engagement with the end of the finger I65, whereupon the finger I may swing in counterclockwise direction from the. position. in which it is shown. in Fig. 2.0. to the position in which it. is. shownv in Fig. 21 to engage a stop I11 which. is retractably mounted. on the latching lever I66. This stop [11 1s positioned so as to stop the upward movement oi the clutch operating handle L80. in its neutral position, so that at this time th clutch actuating bar I45 will be returned to neutral position, and the clutch I6 wil1 be neutral or inoperative. In this manner the tap will be stopped in the position determined by the setting of the nuts 44..

A pin I18, carried. by the lever I13, supports an. auxiliary lever I19; the rearward or leftward end I80 of which is adapted to engage the lever I. 8| of a pivotally supported stop lug I82 positioned in the upward path of movement of the leftward end of the lever I13, as shown in Fig. 21. This stop lug I82, when it is positioned as shown in Fig. 21, limits the upward movement of the link I12, to prevent an upward movement. of the link. I 12 which will rotate the latch lever I85 counterclockwise from the positionin which it is shown in Fig. 21, in which position the stop I'I1 engages the finger I85. The operator may at this time reverse the direction of operation of the tapping device so as to retract the tap from the tapped hole, by pressing downwardly on the forward end of the auxiliary lever I19, so that the leftward. end I80 thereof will engage the lever I 8! associated with the stop lug I82, and rotate the stop lug I82 into the position in which it is shown in dotted lines I82, to permit a further clockwise rotation of the lever I3 and accomplish, through the link I'I2, a counterclockwise rotation of the latching lever I86 which will carry the stop I71 downward out of engagement with the finger I85. The spring IE4 may then swing the clutch operating handle 158 into its up position, shown in dotted lines in Fig. 20, and rotate the shaft IfiI and the lever I82 counterclockwise from the position shown in Fig. 22, thereby rotat ing the lever I41 in clockwise direction and raising the clutch actuating 55 from its neutral position to actuate the lower clutch assembly I99 of the clutch I8 to drive the tapping device in reverse direction.

If the oper tor de ires to.- have the tappin device reverse; automatically when. it reaches. the end of the. down movement of the tap, he may retract the stop I11 by swinging it on the latching lever- I66. into the position in which it is shown in Fig. 22-. Then, when the adjusting nuts 44 act through the lever I13 and the link. I12 to rotate the latching lever I58 in counterclockwise direction from the position in which it is shown in Fig. 20 to releasethe shoulder I58 from engagement with the finger I65, the finger I will be permitted. to swing into the position in which it is shown in Fig. 2.2, whereupon the lever I41 will swing from the position in which it is shown in Fig. 20 through the neutral position in which it is shown in Fig. 21 to the clutchreversing position in which it is shown in Fig. 22.

On the far side of the device, below the clutch operating handle I60, there is a pivot member I83 on which a fnlcrurned. lo l-er I84 is swingable.v This lever I84. has a forwardly roject! ing finger [85. disposed with its end in the path of upward movement of the nuts 4| which areadjustable on the screw 40.. The fulcrumed lever I84 has also an arm I86, the outer end of which is connected through a slotted link I31 with a pivot member I88 carried by the handle I60. Referring to Fig. 252, when the tapping device is operating in up or reverse direction and the upper adjusting nut 4I moves in engagement with the end of the. finger I85, the lever I84 will be thereby rotated in counterclockwise direction into a position indicated by dotted lines I80. to transmit motion throu h the link It? to the arm I60 to move the arm I60 down into its 11611- tral position indicated by dotted lines I58 in Fig. 22, causing the shifting of the mechanism of the clutch I8 into. neutral position and stoppin the power driven elements. of the tappin machine.

An important feature of the invention. resides in the. floating drive. connection I89, shown in detail in Fig. 1.6., for connectin a tap I90 to. the spindle I4 of the. device. The drive connection I89 includes a shell. I 9I which is connected to the lower end of the spindle I 4., this shell ISI having a downwardly faced. recess I02 which receives the. upper portion. of a holder element specifically shown as a cylindrical tap holdin body I93. The body I93 is held in. the. recess I92 in such manner that it may have limited vertical or axial movement by a retainin rin I8 having a threaded. portion which screws into the threaded counterbore I 95 disposed at the lower end of the recess I92. The body I03 has. an axial openin I95 to receive the sha k f th p I80 and s rew I9 are pro ided for clampins he shank of. the. tap I90 in the body .583. The. upper por ion of he body I83 has an pwardly raced recess I98 to accommodate a porion of a sprin I 5.9 whi h acts to resilien ly ur the body I93 toward its lowermost position.

The shell ISI has a shoulder member 200 in the rorm of a key to. cooperate with shoulders 20! and 202. which are formed on the body I93.

The shoulders 20I and 202 are so spaced in angular relation to the shoulder member 200 that a limited free rotary or angular play is provided between the body I93 and the shell I8I. The shoulder member 200 is shown in Fig. 23 in its position against the shoulder 202 of the body, assumed when the tap I 90 is being rotated forwardly in engagement with the part being tapped. When the end or the tappin action is reached, and the direction of rotation of he spindle I4 is reversed for the purpose oi! withdrawing the tap, the spindle l4 and the parts directly connected thereto may rotate through a part of a revolution without reverse rotation of the tap I90, until the shoulder 200 engages the shoulder 2M of the body I93. This rotary movement of the spindle I4 relatively to the tap I90 at the beginning of the reverse rotation of the spindle l4 permits all of the lost motion or play in the drive parts between the quill I4 and the lead screw 33 to be taken up, and reverse rotation of the lead screw 33 is started, before the shoulder member 200 engages the shoulder 2M and starts the reverse rotation of the tap I90. The body I93 is externally slightly smaller than the recess I92 in which it operates, and therefore has a slight universal or rocking movement relatively to the shell IN. The drive connection I89 supports the tap I90 with what may be called a three-way float, since the tap I99 floats in three directions relatively to the shell I9l. It has axial play or float, rotary play or float, and a limited play for axial disalignment.

'It will be'understood that several bodies I93 may be provided having openings I96 to receive taps of different sizes.

I claim as my invention:

1. In a tapping mechanism of the character described, for operating a tap, the combination of: a spindle arranged for axial and rotary movement; power means; a screw and nut assembly connected to said spindle sothat said spindle will be moved axially upon rotation of said screw; a speed change gear mechanism having its output end connected tothe screw of said screw and nut assembly to rotate said screw whereby the movement of the spindle may be correlated to the pitch of the thread of the tap; a spindle drive member engaging said spindle and having sliding engagement therewith to enable axial movement of said spindle relatively to said drive member; drive means, comprising a reversing clutch connecting said power means to said spindle drive member to rotate the same; a drive connection from said spindle drive member to the input of said speed change gear mechanism; means operating said clutch of said drive means whereby the power of said power means may be applied in either forward or reverse direction; and means for connecting a tapto the tap end of said spindle.

2. In a tapping mechanism of the character described for operating a tap, the combination 01': a spindle arranged for axial and rotary movement; power means; a screw and nut assembly connected to said spindle so that said spindle will be moved axially upon rotation of said screw; a speed change gear mechanism having its output end connected to the screw of said screw and nut assembly to rotate said screw whereby the movement of the spindle may be correlated to the pitch of the thread of the tap; a spindle drive member engaging said spindle and having sliding engagement therewith to; enable axial movement of said spindle relatively to said drive member; drive means, comprising a reversing clutch connecting said power means to said spin dle drive member to rotate the same; a drive connection from said spindle drive member to the input of said speed change gear mechanism to simultaneously drive said screw; means operating said clutch of said drive means whereby the power of said power means may be applied in either forward or reverse direction; and a drive connection between the spindle and the tap, said,

drive connection having therein a free rotary play whereby said spindle may rotate relatively to said tap through a limited angular distance, and axial play to compensate for differences in axial movement of said tap and said spindle while the tap is in engagement with the part being tapped.

3. In a tapping mechanism of the character described, for operating a tap, the combination of: a spindle arranged for axial and rotary movement; power means; a screw and nutassembly connected to said spindle so that said spindle will be moved axially upon rotation of said screw; a speed change gear mechanism having its output end connected to the screw of said screw and nut assembly to rotate said screw whereby the movement of the spindle may be correlated to the pitch of the thread-of the tap; a spindle drive member engaging said spindle and having sliding engagement therewith to enable axial movement of said spindle relatively to said drive member; drive means, comprising a reversing I clutch connecting said power means to said spindle drive member to rotate the same; a drive connection from said spindle drive member to the input of said speed change gear mechanism; means operating said clutch of said drive means whereby the power of said power means may be applied in either forward or reverse direc-- tion; and means for connecting said tap to the tap end of said spindle, comprising telescoped parts, one of which is connected to said spindle and the other of which is connected to said tap, said. parts having axial relative movement to compensate for differences in axial movement of said spindle and said tap when the tap is in engagement with the part being tapped, and having driving shoulder means and driven shoulder means permitting a limited free rotary movement of said parts, and spring means operative between said parts to yieldably maintain the same in an initial position.

4. In a tapping machine of the character described for operating a tap, the combination of: a spindle arranged for axial and rotary movement; a-screw connected to said spindle so that axial movement of said screw will produce axialmovement of said spindle; guides disposed on opposite sides of said screw; carriages movable on said guides toward and away from said screw; means for. locking said carriages in positions near to said screw; partial nuts supported by said carriages so as to be moved toward and away from said screw; means operative between said partial nuts and said carriages to adjust said partial nuts toward said screw so that adjusted engagement of said partial nuts with said screw may be obtained; a spindle drive member engaging said spindle and having sliding engagement therewith to enable axial movement of said spindle relatively to said drive member; power driven means connected to said spindle drive member; a drive connection from said spindle drive member to said screw, comprising a speed change gear ad-.

13 axial movement of said screw will produce axial movement of said spindle; guides disposed on opposite sides of said screw; carriages movable on said guides toward and away from said screw;

a pair of crank members mounted in operative relation to said carriages, the swinging ends of said crank members being disposed so as to move transversely to the direction of movement of said carriages and being connected to said carriages so that movement of said crank members will move said carriages into posit-ions near said screw and lock said carriages in said positions when said crank members are disposed substantially perpendicularly to the axis of said screws; partial nuts supported by said carriages so as to be moved toward and away from said screw; nut adjusting means operative between said partial nuts and said carriages to adjust said partial nuts toward said screw so that adjusted engagement of said partial nuts with said screw may be obtained; a spindle drive member engaging said spindle and having sliding engagement therewith to enable axial movement of said spindle relatively to said drive member; means operating to simultaneously rotate said screw, comprising a speed change gear adjustable to 1'0- tate said screw at different speeds; and means connecting a tap to the tap end of said spindle, comprising telescoped parts, one of which is connected to said spindle and the other of which is connected to said tap, said parts having driving shoulder means and driven shoulder means permitting a limited free rotary movement of said parts, and said parts having axial relative movement to compensate for differences in axial movement of said spindle and said tap when the tap is in engagement with the part being tapped.

6. In a tapping machine of the character described, the combination of: a spindle mounted for axial and rotary movement; a spindle drive member engaging said spindle and having sliding engagement therewith to enable axial movement of said spindle relatively to said drive member; means to drivesaid drive member from a source of power; a lead screw supported in spaced relation to said spindle; nut means engaging said lead screw; a spindle-moving connection between said lead screw and said spindle; means to drive said lead screw at difierent speeds relatively tothe speed of said spindle as taps of different sizes are used comprising a drive gear driven by said spindle drive member and speed change gearing connecting said drive gear and said lead screw; and a tap operating connection secured to the front end of said spindle having therein means enabling axial movement of said tap relatively to said spindle and angularly spaced driving and driven shoulders disposed between the spindle and the tap to compensate for lost motion in said speed change gearing.

7. In a tapping machine of the character described, the combination of: a spindle mounted for axial and rotary movement; a spindle drive member engaging said spindle and having sliding engagement therewith to enable axial movement of said spindle relatively to said drive member; means to drive said drive member from a source of power; a lead screw supported in spaced relation to said spindle;- nut means engaging said lead screw; a spindle movin connection between said lead screw and said spindle; and means to drive said lead screw at different speeds relative- 1y to the speed of said spindle as taps of different sizes are used comprising a drive gear driven by said spindle drive member and speed change gearing connecting said drive gear and said lead screw.

EARL B. ELDER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 945,387 Hanson Jan. 4, 1910 1,236,414 Eden Aug. 14, 1917 1,376,791 Baker et a1 May 3, 1921 1,627,236 Galloway May 3, 1927 1,657,274 Neidhammer Jan; 24, 1928 1,670,287 Stickney May 15, 1928 1,673,897 Barnes June 19, 1928 1,763,717 Morgan June 17, 1930 1,793,259 Smeuninx Feb. 17, 1931 1,796,352 Watson Mar. 17, 1931 1,813,480 Brown July 7, 1931 1,836,471 Knight et al Dec. 15, 1931 1,836,675 Lyon Dec. 15, 1931 1,861,350 Mansfield May 31, 1932 1,909,055 Hageman May 16, 1933 1,988,967 Emrick' Jan. 22, 1935 2,028,441 Decker Jan. 21, 1936 2,043,862 Newman June 9, 1936 2,167,401 Foster et al July 25, 1939 2,257,364 Bakewell Sept. 30, 1941 2,327,279 Mansfield Aug. 17, 1943 2,368,359 Hellstrom Jan. 30, 1945 2,376,164 Miller et al May 15, 1945 FOREIGN PATENTS Number Country Date 506,436 Great Britain May 30, 1939 

